Role of central venous-arterial PCO 2 difference in prediction of clinical outcome in ICU septic patients

Background: Identification of tissue hypoxia and hypoperfusion plays an important role in the management of critically ill patients. Although the venous-arterial PCO2 difference (ΔPCO2) cannot serve as a marker of tissue hypoxia, it is considered a marker of the adequacy of venous blood flow (Cardiac output). The present study aimed to evaluate the role of venous-arterial PCO2 gradient in prediction of outcome in septic patients admitted to ICU.Patients and methods: 100 adult patients fulfilled the criteria of severe sepsis or septic shock admitted to Emergency Intensive Care Unit, were divided in two groups according to ΔPCO2. The high ΔpCO2 group (ΔpCO2 > 6 mmHg) included 58 patients and the normal ΔpCO2 (ΔpCO2 ≤ 6 mmHg) included 42 patients. Clinical scoring systems were recorded. Clinical outcome including organ dysfunction and mortality was recorded.Results: The high ΔPCO2 group showed significant lower blood glucose level (p = 0.038) than the normal ΔPCO2 group. Serum lactate, heart rate, and APACHE score were significantly higher in high ΔPCO2 group than normal ΔPCO2 group (p, 0.012, 0.013, and 0.020, respectively). As regard to the clinical outcome, patient mortality was significantly higher (p = 0.042) in high ΔPCO2 group than normal ΔPCO2 group and the number of organ dysfunction was higher in high ΔPCO2 group than normal ΔPCO2 group but not reached a significant level (p = 0.625).Conclusions: ΔPCO2 is a reliable index for early prediction of clinical outcome including organ dysfunction and mortality in patients with sepsis and septic shock.